<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>圆角</title>

    <style>
        .box1 {
            width: 200px;
            height: 100px;
            background-color: deepskyblue;
            /* 挨个设置某一边 */
            /* border-top-left-radius: 50px; */
            /* border-bottom-right-radius: 50px; */
            /* 一次性给所有 */
            border-radius: 100px;
        }
        
        .box2 {
            width: 200px;
            height: 200px;
            background-color: deeppink;
            /* 圆形 */
            border-radius: 50%;
        }
    </style>
</head>

<body>
    <div class="box1"></div>
    <div class="box2"></div>
</body>

</html>